Fig. 5: LBL40 neurons control tibia flexion.

a Segmented and registered images of MDN (red) and LBL40 (green) from ventral and lateral perspectives, and calcium response in LBL40 upon photoactivation of MDN. Same data as in Fig. 3d, see also Supplementary Movie 5. b Confocal images of VNCs of two split-GAL4 lines labeling LBL40 (magenta, nc82 staining; green, anti-GFP staining of CsChrimson-mVenus reporter), and activated voxels (cyan) from calcium imaging experiments using each line. c Selected frames from a representative video of LBL40 activation in a tethered, decapitated fly, during a 5-s red-light stimulus from t = 0 ms. Arrows indicate the femur-tibia angles. Dashed line with arrows in the overlay image indicates sequence of movement. See also Supplementary Movie 6. d Hindleg joint angle time series, showing two representative traces for each genotype. Red shade indicates a 5-s pulse of red light. A short black line marks the origin for each trace (t = 0 s, 0 degrees). Arrows indicate the initial femur-tibia flexion; arrowheads mark steps. The top traces are from the video shown in c. e Maximal femur-tibia joint flexion within 1 s after red-light onset. Bars indicate mean ± s.e.m. P values are shown in italics; two-tailed Mann–Whitney tests. Source data are provided as a Source Data file. f Top, overlaid hindleg femur-tibia joint angles from trials in which LBL40 was activated by a 50 ms light pulse. Bottom, mean joint angle traces, calculated separately for trials with and without a step. Red shading indicates the red-light stimulus. N = 3 flies and n = 105 trials. g Minimum femur-tibia joint angles for non-step and step trials. Bars indicate mean ± s.e.m. P values are shown in italics, two-tailed Mann–Whitney test. Source data are provided as a Source Data file. h Registered segmented image of LBL40 (green), LUM9 (blue), and all synapses (gray, nc82). i Confocal images of VNCs of a LexA line labeling LBL40 and SS50996, labeling LUM9 (green, anti-GFP staining of a myr-GFP or CsChrimson-mVenus reporter; magenta, nc82), and activated voxels (cyan) from calcium imaging of LUM9 upon LBL40 activation. Traces show the averaged responses for LUM9 to LBL40 activation (mean ± s.e.m., N = 6 flies), upon either a single 20-s stimulus or two 1-s light pulses (red shading).